The objective of these experiments is to understand the mechanisms by which Epstein-Barr Virus (EBV) establishes latent infection, persists, and causes neoplasia. The specific aims are (i) To complete the identification of EBV reading frames and proteins that are expressed at various stages of experimental latent or lytic infection of cells, in vitro. (ii) To identify cellular genes whose expression is specifically altered during the course of latent or lytic EBV infection, in vitro. (iii) To further identify viral and cellular genes expressed in cell lines and tumor tissue from patents with EBV associated Lymphoproliferative Disease, Burkitt's Lymphoma, Hodgkin's Disease, Nasopharyngeal Carcinoma, and Gastric Cancer and to further explore the association of EBV with testicular cancers. (iv) To further identify EBV and cellular gene expression in latently infected lymphocytes in the peripheral blood and lymphoid organs of normal people undergoing phlebotomy, biopsy, or surgical resection. (v) To establish and maintain databases of the effects of EBV on cell gene expression.